Process for preparing triarylmethane derivatives

ABSTRACT

A process is described for preparing triarylmethane derivatives of a high purity in an extremely high yield from 3-phenylphthalide derivatives and aniline derivatives or indole derivatives with Friedel-Crafts type catalyst or Friedel-Crafts type catalyst and an oxidizing agent.

This is a division of application Ser. No. 699,584 filed June 24, 1976 now U.S. Pat. No. 4,045,458.

BACKGROUND OF THE INVENTION

This invention relates to a process for preparing colourless chromogenic compounds which form coloured markings upon contact with acidic materials by electron donor-acceptor colour-forming reaction.

Particularly, this invention relates to a novel process for preparing triarylmethane derivatives represented by the following general formulae (I), (II), (III) and (IV): ##STR1## wherein each of R₁ and R₂ is at least one of hydrogen, halogen, nitro group, alkyl group, substituted alkyl group, amino group, substituted amino group, hydroxyl group, substituted hydroxyl group, thiohydroxyl group, or substituted thiohydroxyl group; each of R₃ and R₄ is hydrogen, substituted or unsubstituted alkyl group, cycloalkyl group, substituted or unsubstituted aralkyl group, substituted or unsubstituted aryl group, or substituted or unsubstituted unsaturated alkyl group, or one or both of R₃ and R₄ together with the adjacent nitrogen atom may form a heterocyclic ring; R₅ is at least one of hydrogen, halogen, alkyl group, nitro group, substituted or unsubstituted amino group, substituted or unsubstituted hydroxyl group, substituted or unsubstituted thiohydroxyl group; R₆ is at least one of hydrogen, halogen, lower alkyl group, lower alkoxyl group, amino group, lower alkylamino group, nitro group, phenyl group or phenoxy group; R₇ is hydrogen, alkyl group, aralkyl group or phenyl group; and R₈ is lower alkyl group or substituted or unsubstituted phenyl group.

There are known several methods for preparing triarylmethane derivatives represented by the general formula (I), for example, U.S. Pat. No. Re. 23,024 discloses a method in which the triarylmethane derivative is prepared from m-dimethylamino-benzoic acid and Michler's hydrol by condensation reaction. Another method for preparing triarylmethane derivative by condensation reaction of dimethylaniline with o-phthalaldehydric acid is described in "Beilsteins Handbuch der Organische Chemie", Vol. 14, page 549. However, these methods give triarylmethane derivative in low yields because a large amount of by-products is produced. Furthermore, these methods give only limited compound having a symmetrical structure.

The triarylmethane derivatives having the general formula (II) are novel compounds which are synthesized for the first time by this invention.

The known method for preparing triarylmethane derivatives represented by the general formula (III) and (IV) is disclosed in U.S. Pat. Nos. 2,443,092 and 2,597,965, "Beilsteins Handbuch der Organische Chemie", vol. 18, page 617 and Moriga & Oda, "Kogyo Kagaku Zasshi", vol. 64, page 1226, (1961), in which triarylmethane derivatives are prepared from dimethylaniline and phthalic anhydride by condensation. Another method is described in U.S. Pat. Nos. 3,491,112 and 3,491,116 and in "Beilsteins Handbuch der Organische Chemie", vol 18, pages 618-619, in which benzophenone-2-carboxylic acid is first prepared from dimethylaniline and phthalic anhydride and then triarylmethane derivative is prepared from the resultant benzophenone-2-carboxylic acid and either dimethylaniline derivative or indole derivative.

However, these methods also give triarylmethane derivatives in low yields because of the production of a large amount of by-products. Particularly when substituted phthalic anhydride is used, a large amount of isomers is produced as well, therefore, the yield is more lowered. In addition, substituted phthalic anhydride has such a disadvantage that it is not suitable for industrial production because the process for the production thereof is complicated.

An object of the invention is to provide a novel process for preparing triarylmethane derivatives of a high purity in an extremely high yield.

Other objects and advantages of the invention will become apparent from the following description.

SUMMARY OF THE INVENTION

According to the invention, triarylmethane derivatives represented by the following general formula (I) or (II) are prepared by making 3-phenylphthalide derivatives represented by the general formula (V) react with anilic derivatives represented by the general formula (VI) or with indole derivatives represented by the general formula (VII) in the presence of Friedel-Crafts Type Catalysts: ##STR2## wherein R₁, R₂, R₃, R₄, R₅, R₆, R₇ and R₈ are the same as described above. Further, triarylmethane derivatives represented by the general formula (III) or (IV) are prepared by oxidizing the above obtained triarylmethane derivatives represented by the general formula (I) or (II) with use of oxidizing agents: ##STR3## wherein R₁, R₂, R₃, R₄, R₅, R₆, R₇ and R₈ are the same as described above.

DETAILED DESCRIPTION OF THE INVENTION

3-phenylphthalide derivative represented by the above described general formula (V) which is used in this invention is prepared, as shown as follows, from benzene derivative (VIII) and o-phthalaldehydic acid derivative (IX) by dehydration condensation, or from benzaldehyde derivative (X) and benzoic acid derivative (XI) by dehydration condensation: ##STR4## wherein R₁ and R₂ are the same as described above.

As the typical compounds of 3-phenylphthalide derivatives represented by the above general formula (V) which are used in this invention, the following compounds may be exemplified;

3-(4'-dimethylaminophenyl)phthalide,

3-(4'-dimethylamino-2'-methylphenyl)phthalide,

3-(4'-dimethylamino-2'-methoxyphenyl)phthalide,

3-(4'-dimethylamino-2'-methylthiophenyl)phthalide,

3-(4'-dimethylamino-2'-chlorophenyl)phthalide,

3-(4'-dimethylamino-2'-diethylaminophenyl)phthalide,

3-(4'-diethylaminophenyl)phthalide,

3-(4'-diethylamino-2'-chlorophenyl)phthalide,

3-(4'-diethylamino-2'-methoxyphenyl)phthalide,

3-[4'-(N-ethyl-N-benzyl)aminophenyl]phthalide,

3-[4'-(N-methyl-N-P-tolyl)aminophenyl]phthalide,

3-(4'-pyrrolidinophenyl)phthalide,

4-(julolidine-6'-yl)phthalide,

3-phenyl-6-dimethylaminophthalide,

3-phenyl-6-diethylaminophthalide,

3-[2'(or 3', or 4')-methylphenyl]-6-dimethylaminophthalide,

3-[2'(or 3', or 4')-methoxyphenyl]-6-dimethylaminophthalide,

3-[2'(or 3', or 4')-methoxyphenyl]-6-diethylaminophthalide,

3-[2'-(or 3', or 4')-chlorophenyl]-6-dimethylaminophthalide,

3-[2'-(or 3', or 4')-nitrophenyl]-6-dimethylaminophthalide,

3-[2'-(or 3', or 4')-nitrophenyl]-6-diethylaminophthalide,

3-[2', 3'(or 2', 4')-dimethylphenyl]-6-dimethylaminophthalide,

3-[2', 3'(or 2', 4')-dimethoxyphenyl]-6-dimethylaminophthalide,

3-[2', 3'(or 2',4')-dimethoxyphenyl]-6-diethylaminophthalide,

3-[2',3'(or 2', 4')-dichlorophenyl]-6-dimethylaminophthalide,

3-(2'-methyl-4'-methoxyphenyl)-6-dimethylaminophthalide,

3-(2'-methoxy-4'-methylphenyl)-6-dimethylaminophthalide,

3-[2'(or 3', or 4')-dimethylaminophenyl]-6-dimethylaminophthalide,

3-[2'(or 3', or 4')-dimethylaminophenyl]-6-diethylaminophthalide,

3-[2'(or 3', or 4')-dimethylaminophenyl]-6-N-methyl-N-P-tolylaminophthalide,

3-[2'(or 3', or 4')-dimethylaminophenyl]-6-N-ethyl-N-benzylaminophthalide,

3-[(2'(or 3', or 4')-diethylaminophenyl]-6-dimethylaminophthalide,

3-[2'(or 3', or 4')-diethylaminophenyl]-6-diethylaminophthalide,

3-[2'(or 3', or 4')-dimethylaminophenyl]-5-chloro-6-dimethylaminophthalide,

3-[2'(or 3', or 4')-dimethylaminophenyl]-5-chloro-6-diethylaminophthalide,

3-[2'(or 3', or 4')-dimethylaminophenyl]-6-diallylaminophthalide,

3-[2'(or 3', or 4')-dimethylaminophenyl]-6-dipropargylamino-phthalide,

3-[2'(or 3', or 4')-dimethylaminophenyl]-6-pyrrolidinophthalide,

3-[2'(or 3', or 4')-dimethylaminophenyl]-6-pyrimidinophthalide,

3-[2'(or 3', or 4')-dimethylaminophenyl]-6-morpholinophthalide,

3-(4'-pyrrolidinophenyl)-6-dimethylaminophthalide,

3-(4'-pyrimidinophenyl)-6-dimethylaminophthalide,

3-(julolidine-6'-yl)-6-dimethylaminophthalide,

3-(4'-morpholinophenyl)-6-dimethylaminophthalide,

3-[4'-(N-methyl-N-benzyl)aminophenyl]-6-dimethylaminophthalide,

3-[4'-(N-methyl-N-benzyl)aminophenyl]-6-diethylaminophthalide,

3-[4'-(N-ethyl-N-benzyl)aminophenyl]-6-dimethylaminophthalide,

3-[4'-(N-methyl-N-para-tolyl)aminophenyl]-6-dimethylamino-phthalide,

3-[4'-(N-ethyl-N-para-tolyl)aminophenyl]-6-dimethylaminophthalide,

3-[4'-(N-ethyl-N-para-tolyl)aminophenyl]-6-diethylaminophthalide,

3-(4'-diallylaminophenyl)-6-dimethylaminophthalide,

3-(4'-dipropargylaminophenyl)-6-dimethylaminophthalide,

3-(4'-dimethylamino-2'-methylphenyl)-6-dimethylaminophthalide,

3-(4'-diethylamino-2'-methylphenyl)-6-dimethylaminophthalide,

3-(4'-dimethylamino-2'-chlorophenyl)-6-dimethylaminophthalide,

3-(4'-diethylamino-2'-chlorophenyl)-6-dimethylaminophthalide,

3-(4'-dimethylamino-2'-methoxyphenyl)-6-dimethylaminophthalide,

3-(4'-diethylamino-2'-methoxyphenyl)-6-dimethylaminophthalide,

3-(4'-dimethylamino-2'-methylthiophenyl)-6-dimethylaminophthalide,

3-(4'-diethylamino-2'-methylphenyl)-5-chloro-6-dimethylaminophthalide,

3-(4'-dietylamino-2'-methylphenyl)-5-chloro-6-diethylaminophthalide,

3-(4'-diethylamino-2'-methoxyphenyl)-5-chloro-6-dimethylaminophthalide,

3-(4'-diethylamino-2'-methoxyphenyl)-5-chloro-6-diethylaminophthalide,

3-(4'-dimethylaminophenyl)-6-methoxyphthalide,

3-(4'-diethylaminophenyl)-6-ethoxyphthalide,

3-(4'-diethylaminophenyl)-6-methoxyphthalide and

3-(4'-diethylamino-2'-methoxyphenyl)-6-methoxyphthalide.

Among the above mentioned 3-phenylphthalide derivatives, those having R₂ at the 6 position are preferably used and preferably R₂ is an substituted amino group.

Among the typical compounds of aniline derivatives represented by the above described general formula (VI) which are used in this invention there may be included the following compounds:

    ______________________________________                                         aniline, N--methylaniline,                                                     N--ethylaniline, o-toluidine,                                                  m-toluidine, m-nitroaniline,                                                   m-phenylenediamine, m-chloroaniline,                                           m-bromoaniline, o-anisidine,                                                   o-phenetidine, 2.5-dichloroaniline,                                            N,N--dimethylaniline, N,N--diethylaniline,                                     N--(2-ethylhexyl)-N--methylaniline,                                            N,N--dibutylaniline, N--dodecyl-N--ethylaniline,                               N,N--diethyl-m-toluidine, N,N--diethyl-o-toluidine,                            N,N--dibenzylaniline, N--methyl-N--benzylaniline,                              N--ethyl-N--benzylaniline, diphenylamine,                                      N--benzyldiphenylamine, 4-benzyloxydiphenylamine,                              N--ethyl-4-ethoxydiphenylamine,                                                N--methyldiphenylamine, N--ethyldiphenylamine,                                 N,N--diethyl-o-anisidine, N,N--dimethyl-o-phenetidine,                         N,N--diethyl-m-acetoxyaniline,                                                 N,N--dimethyl-m-nitroaniline,                                                  N,N--diethyl-m-nitroaniline,                                                   N,N--dimethyl-o-chloroaniline,                                                 N,N--dimethyl-m-chloroaniline,                                                 N,N--diethyl-m-chloroaniline,                                                  N,N--dimethyl-o-bromoaniline,                                                  N,N--dimethyl-m-bromoaniline,                                                  N,N--diethyl-o-bromoaniline,                                                   N,N--diethyl-m-bromoaniline,                                                   N,N--diethyl-m-hydroxyaniline,                                                 N,N--bis(β-cyanoethyl)aniline,                                            N,N--bis(β-chloroethyl)aniline,                                           N,N--bis(β-bromoethyl)aniline,                                            N,N--bis(β-ethoxyethyl)aniline,                                           N,N--bis(βL-cyanoethyl)-m-toluidine,                                      N,N--bis(β-chloroethyl)-m-toluidine,                                      N,N--bis(β-bromoethyl)-m-toluisine,                                       N--ethyl-N--(β-chloroethyl)-m-toluidine,                                  N,N--bis(β-ethoxyethyl)-m-toluisine,                                      N--ethyl-N--phenethylaniline,                                                  N--ethoxycarbonylmethyl-N--cyclohexylaniline,                                  N,N--diethyl-m-phenylenediamine,                                               N,N--diethyl-o-phenylenediamine,                                               N,N,N',N',--tetraethyl-m-phenylenediamine,                                     N,N,N',N',--tetraethyl-o-phenylenediamine,                                     N--cyclohexyl-N--methylaniline,                                                N--phenylmorpholine, N--phenylpiperidine,                                      N--phenylpyrrolidine, N--phenylimidazoline,                                    N--phenylpyrazolidine, N--phenylpiperazine,                                    jalolidine, 1-naphthylamine,                                                   N--methyl-1-naphthylamine, N--  ethyl-1-naphthylamine,                         N--phenyl-1-naphthylamine,                                                     N,N--dimethyl-1-naphthylamine,                                                 N,N--diethyl-1-naphthylamine,                                                  5-chloro-N,N--dimethyl-1-naphthylamine,                                        5-bromo-N,N--dimethyl-1-naphthylamine,                                         5-ethoxy-N,N--diethyl-1-naphthylamine,                                         5-benzyloxy-N,N--dimethyl-1-naphthylamine,                                     N--ethyl-N--benzyl-1-naphthylamine,                                            N,N--bis(β-chloroethyl)-1-naphthylamine,                                  N,N--bis(β-bromoethyl)-1-naphthylamine,                                   N,N--bis(β-cyanoethyl)-1-naphthylamine,                                   N,N--bis(β-methoxyethyl)-1-naphthylamine,                                 N,N--bis(β-ethoxyethyl)-1-naphthylamine and                               N--phenyl-N--methyl-1-naphthylamine.                                      

Among the typical compounds of indole derivatives represented by the above mentioned general formula (VII) which are used in this invention there may be included the following compounds:

    ______________________________________                                         2-methylindole, 2-ethylindole,                                                 2-phenylindole, 2-(2'-methylphenyl)indole,                                     2-methyl-5-chloroindole, 2-methyl-5-ethoxyindole,                              2-methyl-7-phenylindole, 2-methyl-5-aminoindole,                               1,2-dimethylindole, 1-methyl-2-phenylindole,                                   1.2.5-trimethylindole, 1.2-dimethyl-5-methoxyindole,                           1.2-dimethyl-5-phenoxyindole,                                                  1.2-dimethyl-5-nitroindole,                                                    1-methyl-2-(4'-chlorophenyl)indole,                                            1-methyl-2-(4'-ethoxyphenyl)indole,                                            1-methyl-2-(4'-ethoxyphenyl)-5-dimethylaminoindole,                            1-benzyl-2-methylindole, 1-benzyl-2.5-dime thylindole                          1-benzyl-2-methyl-5-methoxyindole,                                             1.2-dimethyl-7-phenylindole,                                                   1-phenyl-2.5-dimethylindole,                                                   1-phenyl-2.5-diethylindole and                                                 1.2-dimethyl-5.6-dichloroindole.                                          

In the practice of the invention, 3-phenylphthalide derivative is made to react with aniline derivative or indole derivative in the presence of Friedel-Crafts type catalyst, if necessary, with use of a suitable solvent, at the temperature of 0° to 180° C. for the period between several minutes and several decades of hours.

As a Friedel-Crafts type catalyst, acidic halide Lewis acid catalysts such as AlCl₃, AlBr₃, BeCl₂, CdCl₂, ZnCl₂, BF₃, BCl₃, GaCl₃, GaBr₃, TiCl₄, TiBr₄, ZnCl₄, SnCl₄, SnBr₄, SbCl₅, SbCl₃, BiCl₃, FeCl₃, UCl₄, PF₅, SbF₅, AsF₅ and mixed pentafluorides of Nb and Ta; metal alkyl Lewis acid catalysts such as Al₂ Cl₃ (CH₃)₃ +HCl, AlCl₂ (C₂ H₅), AlCl(C₂ H₅)₂, AlBr₃ (C₂ H₅)₃, Al(C₂ H₅)₂ Br, Al(C₂ H₅)Br₂, Al(C₂ H₅)₃, Al(t-C₄ H₉)₃, Al(i-C₄ H₉)₃, AuBr₂ C₂ H₅, Be(C₂ H₅)₂, BRx₃, MgRx₂, Rx₂ Mg.MgX₂, TiCl₃ CH₃, TiCl₃ (C₂ H₅) and Zn(C₂ H₅)₂, wherein Rx is alkyl group and X is halogen; metal alkoxide Lewis acid catalysts such as Al(OC₆ H₅)₃, aluminum alkoxides, AlCl₂ ORx, AlCl₃.Ti(ORx)₄, Ti(BuO)₄ and Ti(i-PrO)₄, wherein Rx is alkyl group; Br nsted acid catalysts such as, phosphoric acid, polyphosphoric acid, perchloric acid, chlorosulfonic acid, fluosulfonic acid, alkane sulfonic acids such as ethane sulfonic acid, p-toluenesulfonic acid, acetic acid, chloroacetic acids, trifluoroacetic acid, sulfuric acid, hydrogen halides and alkyl halides; acidic oxide and sulfide (acidic chalcide) catalysts such as alumina, Al₂ O₃.CaO, Al₂ O₃.Cr₂ O₃, Al₂ O₃.Fe₂ O₃, Al₂ O₃.V₂ O₃, alumino-silicates (natural), bauxite, bentonite clay, BeO, acid activated clay, chromia (with silica-alumina), Cr₂ O₃ (synthetic), Cr₂ O₃, Fe₂ O₃, floridin, Georgia clay, Gumbrin clay, magnesia (with silica-alumina), molybdenum oxide-alumina, MoS₂, MoS₃, MoS₂.CoS, montmorillonite clay, nickel-alumina, P₂ O₅, silica-alumina, thoria (with silica-alumina), ThO₂ (synthetic), TiO₂, WO₃ (with silica-alumina) and zirconia (with silica-alumina); acidic cation exchanger catalysts such as sulfonated coals, sulfonated phenol-formaldehyde resins, sulfonated divinylbenzene cross linked polymers and exchangers with carboxyl group, phenol group or alumina-silicate skeleton; metathetic cation forming substances such as AgAsF₆, AgClO₄, AgBF₄, AgNO₃, AgOOCCF₃, AGPO₄, AgPF₆, AgSbF₆, Ag₂ SO₄, AgNbF₆, AgTaF₆ and AgTi₂ F₉ ; and the mixtures thereof may be used.

Among the above Friedel-Crafts type catalyst acidic halide Lewis acid catalysts, Br nsted acid catalysts, acidic oxide catalysts, metal alkyl Lewis acid catalysts and metal alkoxide acid catalysts are preferably used because they are highly reactive and economical. Particularly, acidic halide Lewis acid catalysts, Br nsted acid catalysts and acidic oxide catalysts are most preferable.

Referring to the amount of such Friedel-Crafts type catalysts, it may be controlled properly according to the kinds of the starting materials, but it is preferable to use them in amounts equimolar with respect to 3-phenylphthalide derivative or more.

As a solvent, benzene, toluene, alkylbenzene, chlorobenzene, dichlorobenzene, bromobenzene, nitrobenzene, alkylnaphthalene, ethylene chloride, chloroform, tetrachloromethane, tetrachloroethane, nitromethane, nitroethane, nitropropane, carbon disulfide, kerosene, high-boiling naphtha, etc. are preferably used. In order to increase the rate of reaction and to minimize the amount of catalyst, it is preferable that such a solvent should not be used or the amount of the solvent should be minimized even when it is used. On the other hand, the excess amount of solvent is preferably used for the purpose of control of the reaction temperature, homogenization of reaction, extraction or the resultant product, etc. Therefore, the solvent should be used as occasion demands.

In this invention, triarylmethane derivatives represented by the general formula (III) or (IV) are obtained by oxidation of the above obtained triarylmethane derivatives represented by the general formula (I) or (II) with use of an oxidizing agent. Triarylmethane derivative represented by the general formula (I) or (II) is dissolved in acidic aqueous solutions such as hydrochloric acid solution and sulfuric acid solution, alkaline aqueous solutions such as caustic soda solution and caustic potash solution, or organic solvents such as alcohols, lower aliphatic carboxylic acids, ethers, ketones, aromatic hydrocarbons, and thereafter an oxidizing agent is added to the solution, and then the oxidation is carried out at the temperature of 0° to 500° C. for the period between several minutes and several decades of hours.

As an oxidizing agent, manganese compounds such as permanganates, manganates, managanese dioxide, manganese(III) salts and manganese acetate; chromic acid compounds such as chromic anhydride, chromic acid, perchromates, alkyl esters of chromic acid and chromyl chloride; lead compounds such as PbO, PbO₂ and Pb(OCOCH₃)₄ ; copper compounds such as CuO, Cu(OH)₂, CuSO₄, Cu(OCOCH₃)₂, CuCl₂ and CuBr₂ ; cobalt compounds such as Co₂ (SO₄)₃ and Co₃ O₄ ; cerium compounds such as CeO₂, Ce(SO₄)₂ and Ce(SO₄)₃ ; bismuth compounds such as Na BiO₃, BiO and Bi(OCOCH₃)₂ ; silver compounds such as Ag₂ O, AgOCOCH₃ and AgNO₃ ; iron compounds such as FeCl₃, Fe₂ (SO₄)₃ and potassium ferricyanate; SeO₂ ; RuO₄ ; OsO₄ ; inorganic peroxides such as hydrogen peroxide, Fenton's reagent, persulfuric acid and salts thereof; organic peroxides such as performic acid, peracetic acid, perpropionic acid, perbutyric acid, perbenzoic acid, monoperphthalic acid, monoperterephthalic acid, monopersuccinic acid and trifluoroperacetic acid; halides such as hypochlorites, chlorates, hypobromites and bromates; oxygen; ozone; ultraviolet ray; sulfoxides; amine oxides; and chloranil are preferably used. The amount of oxidizing agent may be controlled according to the kinds of oxidizing agent to be used, but it may be usually used in an excess of a stoichiometric amount based on the amount of said triarylmethane derivatives having the general formula (I) or (II).

When the compounds having an oxidizing function such as FeCl₃, FeBr₃, AgNO₃, CuCl₂ and peracetic acid are used as a Friedel-Crafts type catalyst in the preparation of triarylmethane derivatives represented by the general formula (I) or (II) from 3-phenylphthalide derivatives and aniline derivatives or indole derivatives, the resultant triarylmethane derivatives represented by the general formula (I) or (II) are instantaneously oxidized to form triarylmethane derivatives represented by the general formula (III) or (IV).

Namely, the reaction of a 3-phenylphthalide derivative with an aniline derivative or an indole derivative to form a triarylmethane derivative having the general formula (I) or (II) is immediately followed by and concurrently occurs with the oxidizing reaction to form said triarylmethane derivative having the general formula (III) or (IV). For this purpose Friedel-Crafts type catalysts may preferably be used in an excess of the total amount of an equimolar amount with respect to said 3-phenylphthalide derivative and a stoichiometric amount based on the amount of said triarylmethane derivative having the general formula (I) or (II)

The process of the invention for the preparation of triarylmethane derivatives from 3-phenylphthalide derivatives is a novel method which has never been described in any literature. The process of the invention gives triarylmethane derivatives at high purities and in extremely high yields. In addition, the process of the invention makes it possible to prepare the various novel triarylmethane derivatives which could not be synthesized by any conventional methods.

The triarylmethane derivatives obtained in this invention form coloured markings upon contact with acidic substances such as solid acids, e.g., acid clay, activated clay, attapulgite, zeolite, kaolin, bentonite and silicates; and organic acidic materials such as phenol-formaldehyde polymers, phenol-acetylene polymers, maleic acid rosin resin, ethylene-maleic acid anhydride polymers, salicylic acid-aldehyde polymers, salicylic acid-acetylene polymers, polyvalent metal salts of those polymers mentioned above, aromatic carboxylic acids, e.g., salicylic acid and salicylic acid derivatives, and polyvalent metal salts of aromatic carboxylic acids by an electron donor-acceptor colour-forming reaction, therefore, they may be utilized as colourless chromogenic compounds (i.e. electron donor) in various fields which utilize such a reaction. For example, triarylmethane derivatives of the invention can be utilized for the production of pressure sensitive copying sheet which is disclosed in U.S. Pat. Nos. 2,730,456 and 2,730,457 and Japanese Pat. No. 511,757, heat sensitive copying sheet which is disclosed in U.S. Pat. Nos. 3,451,338 and 3,539,375, hectographic copying sheet, electron beam sensitive recording sheet, photosensitive sheet, electrographic heat sensitive recording sheet, ultrasonic recording sheet, toner for Xerox type copying sheet, and leuco ink.

PREFERRED EMBODIMENT OF THE INVENTION

The following examples serve to illustrate the invention in more detail although the invention is not limited to the examples.

EXAMPLE 1

30 g of 3-(p-dimethylaminophenyl)-6-dimethylaminophthalide and 13 g of dimethylaniline were dissolved in 250 cc of tetrachloroethane. 14 g of anhydrous aluminum chloride was added to the solution and the resultant mixture was heated at 50° C. for 3 hours with stirring. After the termination of reaction, 30% aqueous solution of caustic soda was added to dissolve aluminum chloride while cooling the mixture with ice. Then, the tetrachloroethane phase was separated with the aid of a separatory funnel, and then stream distilled to remove the unreacted dimethylaniline and tetrachloroethane. The remaining aqueous phase was neutralized with acetic acid to obtain a pale yellow solid. The yield was 42 g. This solid was recrystallized from benzene to obtain colourless crystals having a melting point (hereinafter referred to as m.p.) of 201° C. The obtained crystal results in a blue colouration when it is subjected to light on silica gel. This compound is triarylmethane represented by the following formula: ##STR5##

EXAMPLE 2

30 g of 3-(p-dimethylaminophenyl)-6-dimethylaminophthalide and 17 g of N,N-diethyl-m-toluidine were dissolved in 300 cc of benzene. After the addition of 14 g of zinc chloride, the mixture was heated at 80° C. for 5 hours with stirring. After cooling, the resultant precipitate was filtered and then dried. The obtained precipitate was dissolved in dilute hydrochloric acid, and then the pH of the solution was adjusted at 4.0 with an aqueous solution of caustic soda to form a yellow precipitate. This precipitate was filtered and then dried. The yield was 45 g. Recrystallization from benzene gave triarylmethane represented by the following formula in the form of colourless crystals whose m.p. was 255°-260° C. This compound turns in blue colour upon exposure to light on TCL. ##STR6##

EXAMPLE 3

Example 1 was repeated except that 26 g of 3-(p-dimethylaminophenyl)phthalide was used instead of 30 g of 3-(p-dimethylaminophenyl)-6-dimethylaminophthalide to obtain 32 g of triarylmethane represented by the following formula whose m.p. was 194°-195° C. in the form of colourless crystals. This compound becomes bluish green upon exposure to light on silica gel. ##STR7##

EXAMPLE 4

Example 1 was repeated except that 29 g of 3-(o-methoxyphenyl)-6-dimethylaminophthalide was used instead of 30 g of 3-(p-dimethylaminophenyl)-6-dimethylaminophthalide to obtain 38 g of triarylmethane represented by the following formula whose m.p. was 237°-238° C. in the form of colourless crystals (Recrystallized from acetic acid-methanol). This compound becomes bluish green upon exposure to light on silica gel. ##STR8##

EXAMPLE 5

Example 1 was repeated except that 13.5 g of 2-methylindole was used instead of 13 g of dimethylaniline to obtain 34 g of triarylmethane having the following formula in the form of colourless crystals. This compound becomes violet upon exposure to light on silica gel. ##STR9##

EXAMPLE 6

Example 1 was repeated except that 29 g of 3-(o-methoxyphenyl)-6-dimethylaminophthalide and 13.5 g of 2-methylindole were used instead of 30 g of 3-(p-dimethylaminophenyl)-6-dimethylaminophthalide and 13 g of dimethylaniline, respectively, to obtain 29 g of triarylmethane having the following structure whose m.p. was 203°-205° C. in the form of colourless crystals (Recrystallized from methanol). This compound becomes blue black upon exposure to light on silica gel. ##STR10##

EXAMPLE 7

Example 1 was repeated except that 32 g of 3-(3', 4'-dimethoxyphenyl)-6-dimethylaminophthalide and 13.5 g of 2-methylindole were used, respectively, instead of 30 g of 3-(p-dimethylaminophenyl)-6-dimethylaminophthalide and 13 g of dimethylaniline to obtain 33 g of triarylmethane having the following structure whose m.p. was 230°-232° C. in the form of colourless crystals (Recrystallized from methanol). This compound becomes bluish violet upon exposure to light on silica gel. ##STR11##

EXAMPLE 8

Example 1 was repeated except that 19.5 g of 2-phenylindole was used instead of 13 g of dimethylaniline to obtain 34 g of triarylmethane having the following structure in the form of colourless crystals. This compound becomes blue upon exposure to light on silica gel. ##STR12##

EXAMPLE 9

Example 1 was repeated except that 32 g of 3-(2',4'-dimethoxyphenyl)-6-dimethylaminophthalide and 13.5 g of 2-methylindole were used, respectively, instead of 30 g of 3-(p-dimethylaminophenyl)-6-dimethylaminophthalide and 13 g of dimethylaniline to obtain 27 g of triarylmethane having the following structure whose m.p. was 202°-203° C. in the form of colourless crystals (Recrystallized from methanol). This compound becomes bluish violet upon exposure to light on silica gel. ##STR13##

EXAMPLE 10

Example 1 was repeated except that 30 g of 3-(p-dimethylaminophenyl)-6-ethoxyphthalide was used instead of 30 g of 3-(p-dimethylaminophenyl)-6-dimethylaminophthalide to obtain 39 g of triarylmethane having the following structure whose m.p. was 197°-198° C. in the form of colourless crystals. This compound becomes bluish green upon exposure to light on silica gel. ##STR14##

EXAMPLE 11

Example 1 was repeated with use of the various starting materials and catalysts shown in the following table instead of 3-(p-dimethylaminophenyl)-6-dimethylaminophthalide, dimethylaniline and anhydrous aluminum chloride to obtain the various triarylmethane compounds shown in the following table. The colours formed upon exposure to light on silica gel are shown in the following table as well.

    __________________________________________________________________________                         aniline or                                                 3-phenylphthalide   indole de-       resultant                                 derivatives         rivatives catalysts                                                                             compounds            color                __________________________________________________________________________      ##STR15##                                                                                          ##STR16##                                                                               ZnCl.sub.2                                                                             ##STR17##           Blue                  ##STR18##                                                                                          ##STR19##                                                                               "                                                                                      ##STR20##           "                     ##STR21##          "         "                                                                                      ##STR22##           "                     ##STR23##          "         "                                                                                      ##STR24##           "                     ##STR25##          "         "                                                                                      ##STR26##           "                     ##STR27##          "         Ti(i-PrO).sub.4                                                                        ##STR28##           "                     ##STR29##          "         SiO.sub.2Al.sub.2 O.sub.3                                                              ##STR30##           Bluish green          ##STR31##          "         "                                                                                      ##STR32##           Bluish green          ##STR33##                                                                                          ##STR34##                                                                               ZnCl.sub.2                                                                             ##STR35##           Blue black            ##STR36##                                                                                          ##STR37##                                                                               "                                                                                      ##STR38##           Bluish green          ##STR39##                                                                                          ##STR40##                                                                               Al(C.sub.2 H.sub.5).sub.3                                                              ##STR41##           Blue                  ##STR42##                                                                                          ##STR43##                                                                               ZnCl.sub.2                                                                             ##STR44##           Blue black            ##STR45##                                                                                          ##STR46##                                                                               "                                                                                      ##STR47##           Bluish green          ##STR48##                                                                                          ##STR49##                                                                               CH.sub.3 COOH                                                                          ##STR50##           Blue                  ##STR51##                                                                                          ##STR52##                                                                               CF.sub.3 COOH                                                                          ##STR53##           "                     ##STR54##                                                                                          ##STR55##                                                                               SiO.sub.2                                                                              ##STR56##           "                     ##STR57##                                                                                          ##STR58##                                                                               Clay(acid activated)                                                                   ##STR59##           Blue                 __________________________________________________________________________

EXAMPLE 12

Example 1 was repeated except that 33 g of anhydrous ferric chloride was used instead of 14 g of anhydrous aluminum chloride to obtain 16 g of compound having the following structure whose m.p. was 180° C. in the form of colourless crystals (Recrystallized from benzene-methanol). This compound becomes blue upon contact with silica gel. ##STR60##

EXAMPLE 13

Example 12 was repeated with use of the various starting materials and catalysts shown in the following table instead of 3-(p-dimethylaminophenyl)-6-dimethylaminophthalide, dimethylaniline and anhydrous ferric chloride to obtain the various triarylmethane compounds shown in the following table. Those compounds produce the various colours shown in the following table immediately upon contact with silica gel.

    __________________________________________________________________________                           aniline or                                               3-phenylphthalide     indole de-      resultant                                derivatives           rivatives  catalysts                                                                           compounds            color               __________________________________________________________________________      ##STR61##                                                                                            ##STR62## FeBr.sub.3                                                                           ##STR63##           Blue                 ##STR64##                                                                                            ##STR65## CuCl.sub.2                                                                           ##STR66##           "                    ##STR67##                                                                                            ##STR68## FeCl.sub.3                                                                           ##STR69##           "                    ##STR70##                                                                                            ##STR71## AgNO.sub.3                                                                           ##STR72##           Violet              __________________________________________________________________________

EXAMPLE 14

33 g of 3-(m-diethylaminophenyl)-6-dimethylaminophthalide and 13 g of dimethylaniline were dissolved in 300 cc of tetrachloroethane. 14 g of anhydrous aluminum chloride was added to the solution, and then the mixture was heated at 50° C. for 3 hours with stirring. After the termination of reaction, 30% aqueous solution of caustic soda was added to the mixture to dissolve aluminum chloride while cooling with ice. Tetrachloroethane phase was steam distilled to remove unreacted dimethylaniline and tetrachloroethane. The remaining aqueous phase was neutralized with acetic acid to obtain a white solid. This solid was dissolved in 600 cc of 2.5% aqueous solution of caustic soda, and then heated at 50° C. 600 cc of 5% aqueous solution of potassium persulfate was added dropwise to the above solution, and then the mixture was heated at 60° C. for 3 hours. After the termination of reaction, the resultant precipitates were filtered and recrystallized from methanol to obtain 31 g of 3-(m-diethylaminophenyl)-3-(p-dimethylaminophenyl)- 6-dimethylaminophthalide having the following structure whose m.p. was 177°-178° C. in the form of colourless crystals. This compound become green on contact with silica gel. ##STR73##

EXAMPLE 15

Example 14 was repeated except that 29 g of 3-(p-methoxyphenyl)-6-dimethylaminophthalide and 19.5 g of 2-phenylindole were used, respectively, instead of 33 g of 3-(m-diethylaminophenyl)-6-dimethylaminophthalide and 13 g of dimethylaniline to obtain 24 g of 3-(p-methoxyphenyl)-3-(2-phenylindole-3-yl)-6-dimethylaminophthalide having the following structure whose m.p. was 224°-225° C. in the form of colourless crystals (Recrystallized from benzene-methanol). This compound becomes blue black on contact with silica gel. ##STR74##

EXAMPLE 16

Example 14 was repeated except that 32 g of 3-(3,4-dimetoxyphenyl)-6-dimethylaminophthalide and 19.5 g of 2-phenylindole were used instead of 33 g of 3-(m-diethylaminophenyl)-6-dimethylaminophthalide and 13 g of dimethylaniline to obtain 21 g of 3-(3',4'-dimetoxyphenyl)-3(2'-phenylindole-3'-yl)-6-dimethylaminophthalide having the following structure whose m.p. was 235°-236° C. in the form of colourless crystals (Recrystallized from benzene-methanol). This compound becomes blue black upon contact with silica gel. ##STR75##

EXAMPLE 17

Example 14 was repeated except that 32 g of 3-(2',4'-dimethoxyphenyl)-6-dimethylaminophthalide and 19.5 g of 2-phenylindole were used instead of 33 g of 3-(m-diethylaminophenyl)-6-dimethylaminophthalide and 13 g of dimethylaniline to obtain 30 g of 3-(2',4'-dimethoxyphenyl)-3-(2'-phenylindole-3'-yl)-6-dimethylaminophthalide having the following structure whose m.p. was 239°-240° C. in the form of colourless crystals (Recrystallized from benzene-methanol). This compound becomes blue black upon contact with silica gel. ##STR76##

EXAMPLE 18

Example 14 was repeated except that 35 g of 3-(juloidine-6'-yl)phthalide and 15 g of 1,2-dimethylindole were used instead of 33 g of 3-(m-diethylaminophenyl)-6-dimethylaminophthalide and 13 g of dimethylaniline to obtain 28 g of 3-(juloidine-6'-yl)-3-(1',2'-dimethylindole-3'-yl)phthalide having the following structure whose m.p. was 259°-260° C. in the form of colourless crystals (Recrystallized from alcohol). This compound becomes violet upon contact with silica gel. ##STR77##

EXAMPLE 19

Example 14 was repeated except that 38 g of 3-{p-di(n-butyl)aminophenyl}phthalide and 15 g of 1,2-dimethylindole were used instead of 33 g of 3-(m-diethylaminophenyl)-6-dimethylaminophthalide and 13 g of dimethylaniline to obtain 33 g of 3-{p-di(n-butyl)aminophenyl}-3-(1',2'-dimethylindole-3'-yl)phthalide having the following structure whose m.p. was 140°-142° C. in the form of colourless crystals (Recrystallized from benzene-methanol). This compound becomes violet on contact with silica gel. ##STR78##

EXAMPLE 20

Example 14 was repeated with use of the following various 3-phenylphthalide derivatives instead of 3-(m-diethylaminophenyl)-6-dimethylaminophthalide, and the following various aniline or indole derivatives instead of dimethylaniline to obtain the triarylmethane derivatives shown in the following table. The colours which were formed on contact with silica gel are shown in the following table as well.

      3-phenylphthalide derivatives aniline or indole derivatives resultant      compound m.p. color       ##STR79##       ##STR80##       ##STR81##       89-93° C. Blue       "      ##STR82##       ##STR83##       147-149° C. "       "      ##STR84##       ##STR85##       187-189° C. "       "      ##STR86##       ##STR87##       68-70° C. "       "      ##STR88##       ##STR89##       -- "       "      ##STR90##       ##STR91##       -- "       "      ##STR92##       ##STR93##       143-145° C. "       "      ##STR94##       ##STR95##       -- Green       "      ##STR96##       ##STR97##       -- Blue       "      ##STR98##       ##STR99##       -- "       "      ##STR100##       ##STR101##       -- "       "      ##STR102##       ##STR103##       -- "       ##STR104##       ##STR105##       ##STR106##       -- Bluishgreen       ##STR107##       "       ##STR108##       -- Bluishgreen       ##STR109##       "       ##STR110##       -- Bluishgreen       ##STR111##       ##STR112##       ##STR113##       -- Bluishgreen       ##STR114##       ##STR115##       ##STR116##       180-182° C. Blue       ##STR117##       "       ##STR118##       191-192° C. "       ##STR119##       "       ##STR120##       215-216° C. "        "      ##STR121##       ##STR122##       108-115° C. "       ##STR123##       ##STR124##       ##STR125##       200-202° C. "       ##STR126##       ##STR127##       ##STR128##       223-225° C. blue       ##STR129##       ##STR130##       ##STR131##       238-239° C. reddishviolet       ##STR132##       "       ##STR133##       242-243° C. reddishviolet       ##STR134##       ##STR135##       ##STR136##       95-98° C. violet       ##STR137##       ##STR138##       ##STR139##       102-105° C. bluishgreen       ##STR140##       ##STR141##       ##STR142##       125-128° C. bluishgreen       ##STR143##       ##STR144##       ##STR145##       263-265° C. blueblack       "      ##STR146##       ##STR147##       235-237° C. green       ##STR148##       ##STR149##       ##STR150##       220-223° C. blue       ##STR151##       ##STR152##       ##STR153##       -- violet       "      ##STR154##       ##STR155##       -- "       "      ##STR156##       ##STR157##       -- "       ##STR158##       ##STR159##       ##STR160##       -- violet

EXAMPLE 21

10 g of the triarylmethane derivative obtained in Example 2 was dissolved in 100 cc of ethylene glycol monomethyl ether. 7 g of chloranil was added to the solution, and then the mixture was heated at 50° C. for one hour with stirring. The reaction mixture was poured into 2000 cc of water. After the adjustment of the pH of the mixture solution at less than 2 with dilute hydrochloric acid, the insoluble material was removed by filtration. The pH of the filtrate was adjusted at 4 with an aqueous solution of caustic soda to obtain a pale blue solid. After drying, the solid was recrystallized from benzenemethanol to obtain 3-(p-dimethylaminophenyl)-3-(2'-methyl-4'-diethylaminophenyl)-6-dimethylaminophthalide having the following structure whose m.p. was 212°-214° C. in the form of colourless crystals. This compound immediately becomes blue on contact with silica gel. ##STR161##

EXAMPLE 22

Example 21 was repeated with use of the various triarylmethane derivatives obtained in Examples 3 to 11 and the various oxidizing agents and solvents as shown in the following table to prepare the various triarylmethane lactone derivatives. The colours which were formed on silica gel are shown in the following table as well.

      triarylmethane  oxidizing resultant   derivatives solvents agents      compounds m.p. color       ##STR162##       aqueoussolutionofcausticsoda KM.sub.n       O.sub.4      ##STR163##       190-191° C. bluishgreen       ##STR164##       dilutehydro-chloricacid FeCl.sub.3       ##STR165##       208-210° C. bluishgreen       ##STR166##       dilutesulfuricacid Fe.sub.2       (SO.sub.4).sub.3      ##STR167##       203-205°  C. violet       ##STR168##       aqueoussolutionofcausticsoda NaClO       ##STR169##       235-236° C. blueblack       ##STR170##       aceticacid CH.sub.3       COOOH      ##STR171##       244-245° C. bluishviolet       ##STR172##       aqueoussolutionofcausticsoda AgNO.sub.3       ##STR173##       252-253° C. blue       ##STR174##       dilutehydro-chloricacid PbO.sub.2       ##STR175##       213-215° C. bluishviolet       ##STR176##       aqueoussolutionofcausticsoda K.sub.2 S.sub.2       O.sub.8      ##STR177##       167-168° C. bluishgreen       ##STR178##       dilutehydro-chloricacid PbO.sub.2       ##STR179##       172-175° C. blue       ##STR180##       dilutehydro-chloricacid PbO.sub.2       ##STR181##       80-85° C. blue       ##STR182##       dilutehydro-chloricacid CuCl.sub.2       ##STR183##       -- blue       ##STR184##       aqueoussolutionofcausticsoda Na.sub.2 S.sub.2       O.sub.8      ##STR185##       -- blue       ##STR186##       aqueoussolutionofcausticsoda Na.sub.2 S.sub.2       O.sub.8      ##STR187##       -- blue       ##STR188##       aqueoussolutionofcausticsoda Na.sub.2 S.sub.2       O.sub.8      ##STR189##       -- blue       ##STR190##       dilutesulfuricacid K.sub.2 Cr.sub.2       O.sub.7      ##STR191##       186-187° C. bluish green       ##STR192##       aqueoussolutionofcausticsoda H.sub.2       O.sub.2      ##STR193##       218° C. bluishgreen       ##STR194##       aqueoussolutionofcausticsoda H.sub. 2       O.sub.2      ##STR195##       204-206° C. blueblack       ##STR196##       aqueoussolutionofcausticsoda H.sub.2       O.sub.2      ##STR197##       -- bluishgreen       ##STR198##       aqueoussolutionofcausticsoda H.sub.2       O.sub.2      ##STR199##       viscoussolid blue       ##STR200##       aqueoussolutionofcausticsoda H.sub.2       O.sub.2      ##STR201##       -- blueblack       ##STR202##       ethyleneglycolmono-methylether chlora-nil       ##STR203##       151-152° C. bluishgreen       ##STR204##       ethyleneglycolmono-methylether chlora-nil       ##STR205##       183-186° C. blue       ##STR206##       aqueoussolutionofcausticsoda K.sub.2 S.sub.2       O.sub.8      ##STR207##       -- blue       ##STR208##       aqueoussolutionofcausticsoda K.sub.2 S.sub.2       O.sub.8      ##STR209##       -- blue       ##STR210##       aqueoussolutionofcausticsoda K.sub.2 S.sub.2       O.sub.8      ##STR211##       -- blue 

What we claim is:
 1. A process for preparing a triarylmethane derivative having the structural formula ##STR212## wherein each R₁ and R₂ represents at least one of hydrogen, halogen, nitro group, alkyl group, amino group, alkyl-, benzyl-, phenyl-, tolyl-, or pentylene-substituted amino group, hydroxyl group, alkyl-substituted hydroxyl group, thiohydroxyl group or alkyl-substituted thiohydroxyl group, each R₃ and R₄ represents hydrogen, cyano-, hydroxyl-, halogen-, methoxy-, ethoxy-, or ethoxycarbonyl-substituted or unsubstituted alkyl group, cycloalkyl group, alkyl-substituted or unsubstituted aralkyl group, aryl group, or unsaturated alkyl group, or one or both of R₃ and R₄ together with the adjacent nitrogen atom may form a morpholine ring, a pyrrolidine ring, a pyrazolidine ring, a piperidine ring, an imidazoline ring, a piperazine ring, or a pyrimidine ring, R₅ represents at least one of hydrogen, halogen, alkyl group, nitro group, lower alkyl-substituted or unsubstituted amino group, lower alkyl-substituted or unsubstituted hydroxyl group, or lower alkyl-substituted or unsubstituted thiohydroxyl group, R₆ represents at least one of hydrogen, halogen, lower alkyl group, lower alkoxyl group, amino group, lower alkylamino group, nitro group, phenyl group or phenoxy group, R₇ represents hydrogen, alkyl group, aralkyl group or phenyl group, R₈ represents an alkyl group or alkyl-, halogen-, or alkoxy-substituted or unsubstituted phenyl group which comprises oxidizing a triarylmethane derivative having the structural formula ##STR213## wherein R₁, R₂, R₃, R₄, R₅, R₆, R₇ and R₈ are the same as described hereinbefore, said triarylmethane derivative having the structural formula (I) or (II) being obtained by the reaction of 3-phenylphthalide having the structural formula ##STR214## wherein R₁ and R₂ are the same as described hereinbefore with the aniline derivative having the structural formula ##STR215## wherein R₃, R₄ and R₅ are the same as described hereinbefore, or with the indole derivative having the structural formula ##STR216## wherein R₆, R₇ and R₈ are the same as described hereinbefore in the presence of a Friedel-Crafts type catalyst.
 2. A process for preparing triarylmethane derivative as defined in claim 1, wherein said 3-phenylphthalide derivatives having the structural formula (V) has R₂ at the 6 position.
 3. A process for preparing triarylmethane derivative as defined in claim 2, wherein said R₂ is at least one alkyl-, benzyl-, phenyl-, tolyl-, or pentylene-substituted amino group.
 4. A process for preparing triarylmethane derivative as defined in claim 1, wherein said Friedel-Crafts type catalyst comprises at least one member selected from the group consisting of acidic halide Lewis acid catalysts, Br nsted acid catalysts, acidic oxide catalysts, metal alkyl Lewis acid catalysts and metal alkoxide Lewis acid catalysts.
 5. A process for preparing triarylmethane derivative as defined in claim 4, wherein said Friedel-Crafts type catalyst comprises at least one member selected from the group consisting of acidic halide Lewis acid catalysts, Br nsted acid catalysts and acidic oxide catalysts.
 6. A process for preparing triarylmethane derivative as defined in claim 1, wherein said Friedel-Crafts type catalyst is used in an equimolar amount with respect to said 3-phenylphthalide derivative or more.
 7. A process for preparing triarylmethane derivative as defined in claim 1, wherein the reaction of said 3-phenylphthalide derivative with said aniline derivative or said indole derivative is carried out a temperature within the range of 0° to 180° C.
 8. A process for preparing triarylmethane derivative as defined in claim 1, wherein said triarylmethane derivative having the general formula (I) or (II) is oxidized with use of an oxidizing agent.
 9. A process for preparing triarylmethane derivative as defined in claim 8, wherein said oxidizing agent is used in an excess of a stoichiometric amount based on the amount of said triarylmethane derivative having the structural formula (I) or (II).
 10. A process for preparing triarylmethane derivative as defined in claim 1, wherein the reaction of said 3-phenylphthalide derivative with said aniline derivative or said indole derivative to form said triarylmethane derivative having the structural formula (I) or (II) is immediately followed by and concurrently occurs with the oxidizing reaction to form said triarylmethane derivative having the structural formula (III) or (IV).
 11. A process for preparing triarylmethane derivative as defined in claim 10, wherein said Friedel-Crafts type catalyst comprises at least one member selected from the group of FeCl₃, FeBr₃, AgNO₃, CuCl₂ or peracetic acid.
 12. A process for preparing triarylmethane derivative as defined in claim 10, wherein said 3-phenylphthalide derivatives having the structural formula (V) has R₂ at the 6 position.
 13. A process for preparing triarylmethane derivative as defined in claim 12, wherein said R₂ is at least one alkyl-, benzyl-, phenyl-, tolyl-, or pentylene-substituted amino group.
 14. A process for preparing triarylmethane derivative as defined in claim 11, wherein said Friedel-Crafts type catalyst is used in an excess of the total amount of an equimolar amount with respect to said 3-phenylphthalide derivative and a stoichiometric amount based on the amount of said triarylmethane derivative having the structural formula (I) or (II).
 15. A process for preparing triarylmethane derivative as defined in claim 10, wherein the reaction of said 3-phenylphthalide derivative with said aniline derivative or said indole derivative is carried out a temperature within the range of 0° to 180° C.
 16. A process for preparing triarylmethane derivatives as defined in claim 1, wherein said triarylmethane derivatives having the structural formula (I) or (II) is oxidized in the presence of at least one oxidizing agent selected from the group consisting of manganese compounds, chromic acid compounds, lead compounds, copper compounds, cobalt compounds, cerium compounds, silver compounds, iron compounds, SeO₂, RuO₄, OsO₄, inorganic peroxides, organic peroxides, halides, oxygen, ozone, ultraviolet rays, sulfoxides, amino acids and chloranil.
 17. A process for preparing triarylmethane derivatives as defined in claim 10, wherein the oxidizing agent is selected from the group consisting of ferric chloride, potassium persulfate, chloranil, potassium permanganate, ferric sulfate, sodium hypochlorite, peracetic acid, silver nitrate, lead peroxide, cupric chloride, potassium dichromate and hydrogen peroxide.
 18. A process for preparing triarylmethane derivatives as defined in claim 1, wherein said oxidation is with at least one oxidizing agent selected from the group consisting of permanganates, manganese dioxide, manganese (III) salts, chromic anhydride, chromic acid, perchromates, alkyl esters of chromic acid, chromyl chloride, lead compounds, copper compounds, cobalt (III) compounds, cerium (IV) compounds, NaBiO₃, bismuthoxide, bismuthacetate, silver (I) compounds, iron (III) compounds, SeO₂, RuO₄, OsO₄, hydrogen peroxide, persulfuric acid, persulfuric acid salts, peroxides of aliphatic or carboxylic acid, hypochlorites, chlorates, hypobromites, bromates, oxygen, ozone, dimethyl sulfoxides, amine oxides and chloranil.
 19. A process for preparing triarylmethane derivatives as defined in claim 1, wherein said oxidation is with at least one oxidizing agent selected from the group consisting of permanganates, manganese dioxide, manganese (III) salts, manganese acetate, chromic anhydride, chromic acid, perchromates, chromyl chloride, PbO, PbO₂, Pb(OCOCH₃)₄, CuO, Cu(OH)₂, CuSO₄, Cu(OCOCH₃)₂, CuCl₂, CuBr₂, Co₂ (SO₄)₃, Co₃ O₄, CeO₂, Ce(SO₄)₂, Ce(SO₄)₃, NaBiO₃, BiO, Bi(OCOCH₃)₂, Ag₂ O, AgOCOCH₃, AgNo₃, FeCl₃, Fe₂ (SO₄)₃, potassium ferricyanate, SeO₂, RuO₄, OsO₄, hydrogen peroxide, persulfuric acid, persulfuric acid salts, performic acid, peracetic acid, perpropionic acid, perbutyric acid, perbenzoic acid, monoperphthalic acid, monoperterephthalic acid, monopersuccinic acid, trifluoroperacetic acid, hypochlorites, chlorates, hypobromites, bromates, oxygen, ozone, sulfoxides, amine oxides and chloranil.
 20. A process for preparing a triarylmethane derivative having the structural formula: ##STR217## wherein each R₁ and R₂ represent at least one of hydrogen, halogen, a nitro group, an alkyl group, an amino group, an alkyl-, benzyl-, phenyl-, tolyl-, or pentylene-substituted amino group, a hydroxyl group, an alkyl-substituted hydroxyl group, a thiohydroxyl group or an alkyl-substituted thiohydroxyl group, R₆ represents at least one of hydrogen, halogen, lower alkyl group, lower alkoxyl group, amino group, lower alkylamino group, nitro group, phenyl group or phenoxy group, R₇ represents hydrogen, alkyl group, aralkyl group or phenyl group, R₈ represents an alkyl group or alkyl-, halogen-, or alkoxy-substituted or unsubstituted phenyl group which comprises reacting a 3-phenylphthalide derivative having the structural formula: ##STR218## wherein R₁ and R₂ are the same as described hereinabove, with an indole derivative having the structural formula: ##STR219## wherein R₆, R₇ and R₈ are the same as hereinabove defined, in the presence of a Friedel-Crafts type catalyst.
 21. A process for preparing a triarylmethane derivative having the structural formula: ##STR220## wherein each R₁ and R₂ represents at least one of hydrogen, halogen, nitro group, alkyl group, amino group, alkyl-, benzyl-, phenyl-, tolyl-, or pentylene-substituted amino group, hydroxyl group, alkyl-substituted hydroxyl group, thiohydroxyl group or alkyl-substituted thiohydroxyl group, R₆ represents at least one of hydrogen, halogen, lower alkyl group, lower alkoxyl group, amino group, lower alkylamino group, nitro group, phenyl group or phenoxy group, R₇ represents hydrogen, alkyl group, benzyl group or phenyl group, R₈ represents an alkyl group or alkyl-, halogen-, or alkoxy-substituted or unsubstituted phenyl group which comprises oxidizing a triarylmethane derivative having the structural formula ##STR221## wherein R₁, R₂, R₆, R₇ and R₈ are the same as described hereinbefore with an oxidizing agent, said triarylmethane derivative having the structural formula (II) being obtained by the reaction of 3-phenylphthalide having the structural formula ##STR222## wherein R₁ and R₂ are the same as the described hereinbefore with the indole derivative having the structural formula ##STR223## wherein R₆, R₇ and R₈ are the same as described hereinbefore in the presence of a Friedel-Crafts type catalyst, said oxidizing agent being at least one selected from the group consisting of permanganates, manganese dioxide, manganese (III) salts, chromic anhydride, chromic acid, perchromates, alkyl esters of chromic acid, chromyl chloride, lead compounds, copper compounds, cobalt (III) compounds, cerium (IV) compounds, NaBiO₃, bismuthoxide, bismuthacetate, silver (I) compounds, iron (III) compounds, SeO₂, RuO₄, OsO₄, hydrogen peroxide, persulfuric acid, persulfuric acid salts, peroxides of aliphatic or carboxylic acid, hypochlorites, chlorates, hypobromites, bromates, oxygen, ozone, dimethyl sulfoxides, amine oxides and chloranil.
 22. A process for preparing a triarylmethane derivative as claimed in claim 18 wherein each R₃ and R₄ represents hydrogen, an alkyl group, a benzyl group, or a phenyl group.
 23. A process for preparing a triarylmethane derivative having the structural formula ##STR224## wherein each R₁ and R₂ represents at least one of hydrogen, halogen, nitro group, alkyl group, amino group, alkyl-, benzyl-, phenyl-, tolyl-, or pentylene-substituted amino group, hydroxyl group, alkyl-substituted hydroxyl group, thiohydroxyl group or alkyl-substituted thio-hydroxyl group, each R₃ and R₄ represents hydrogen, cyano-, hydroxyl-, halogen-, methoxy-, ethyoxy-, or ethoxycarbonyl-substituted or unsubstituted alkyl group, cycloalkyl group, alkyl-substituted or unsubstituted aralkyl group, aryl group, or unsaturated alkyl group, or one or both of R₃ and R₄ together with the adjacent nitrogen atom may form a morpholine ring, a pyrrolidine ring, a pyrazolidine ring, a piperidine ring, an imidazoline ring, a piperazine ring, or a pyrimidine ring, R₅ represents at least one of hydrogen, halogen, alkyl group, nitro group, lower alkyl-substituted or unsubstituted amino group, lower alkyl-substituted or unsubstituted hydroxyl group, or lower alkyl-substituted or unsubstituted thiohydroxyl group, R₆ represents at least one of hydrogen, halogen, lower alkyl group, lower alkoxyl group, amino group, lower alkyl-amino group, nitro group, phenyl group or phenoxy group, R₇ represents hydrogen, alkyl group, aralkyl group or phenyl group, R₈ represents an alkyl group or alkyl-, halogen-, or alkoxy-substituted or unsubstituted phenyl group which comprises oxidizing a triarylmethane derivative having the structural formula ##STR225## wherein R₁, R₂, R₃, R₄, R₅, R₆, R₇ and R₈ are the same as described hereinbefore, said triarylmethane derivative having the structural formula (I) or (II) being obtained by the reaction of 3-phenylphthalide having the structural formula ##STR226## wherein R₁ and R₂ are the same as described hereinbefore with the aniline derivative having the structural formula ##STR227## wherein R₃, R₄ and R₅ are the same as described hereinbefore, or with the indole derivative having the structural formula ##STR228## wherein R₆, R₇ and R₈ are the same as described hereinbefore in the presence of a Friedel-Crafts type catalyst. 